A roller conveyor may be powered by a motor housed in a cylindrical roller. In such a conveyor the rollers are typically arranged in sections or zones of 8 or more rollers, with one or two motorized drive rollers. One or both of the terminal rollers of the zone is a drive roller. The rollers between the terminal rollers may be driven from the motorized drive roller as by O-ring-like belts. One or more conveyor belts may extend around the terminal rollers and across the intermediate carrying rollers for better traction, or to carry small products. The conveyor belts restrict air flow to the motorized terminal rollers which can lead to overheating and damage to the motor. The terminal roller, particularly at the transition between an inclined zone and a horizontal or level zone, is subject to impacts from conveyed articles which may damage the motor.